Patent Document 1 discloses an in-wheel motor unit having upper and lower arms suspended from a vehicle body, a motor casing movably sandwiched between the upper and lower arms via a ball joint, and an output shaft rotating with a wheel hub by being supported rotatably with the motor casing via a hub bearing.
[Patent Document 1]
    Japanese Patent Kokai Publication No. JP-2005-81871 A (paragraphs 0013, 0019 and 0024)